The invention relates to a stack conveyor and material handler in the form of a crane, in particular for use in a warehouse with a storage system or the like, for storing rod- or bar-like material.
The apparatus has multiple stack frames disposed in parallel forming arrays but crosswise to the longitudinal extent of the conveyor unit with terminal portions aranged flush with one another in the storeroom longitudinal direction. Arranged in a shelf-like manner, these stack frames are provided with adjacent rows of supporting arms for receiving the rod material; these arms are arranged on the vertical stack frames in row like arrays one ahove the other extending in a longitudinal direction. Ahove the tiers of shelves, a crane is disposed to be movable crosswise to corridors provided between adjacent stack frames. The crane has vertical guides for a horizontal load-bearing beam, disposed parallel to the corridors between stack frames and can be raised and lowered in between the tiers of shelves as well as over and under the stack frames. On one side, protruding horizontally between the rows of supporting arms, a load-bearing beam is disposed with a firmly attached load pickup means comprising prongs or the like extending in a longitudinal direction. By movement of the crane, the prongs can be brought into alignment with the shelves and inserted therein to store or remove material from storage.
In a stack conveyor and material handler of this kind, the crane may comprise a portal crane that moves over the stack, arrays or a bridge crane movable above them wherein the load-bearing beam is let down into the corridors between stacks from the crane above. Conveyors that are movable from underneath the stack arrays are also known, which then raise the load-bearing beams into the corridors between stacks. The invention relates without limitation to all such types, and similar types, of crane construction known in the art.
A crane conveyor and material handler of the type described above is known from U.S. Pat. No. 4,372,724, for example. Together with the particular storage system for rod-like material involved, it serves to provide partitioning machines with material and to return usable leftover material to storage for further use. However, because of the positive connection of the prongs with the load-bearing beam, which is provided for reasons of stability, the only stacks that can be used are those having supporting arms or shelves disposed upon only one side. If the load-bearing beam were provided with corresponding prongs on both sides in the horizontal direction, to enable using stacks provided with shelves on both sides, then the width of the stack corridors would have to be practically douhled, to permit the vertical movement of the load-bearing beam. However, that would mean that to handle the material located on one side, the width of the corridor associated with the other side would be virtually useless and superfluous. Moreover, because the stacks of shelves are provided on only one side, virtually twice as many vertical stack supports are needed, which also means a corresponding additional requirement for stack components and storage space.
In the known case, the prongs have upwardly protruding bosses or mandrels on their free front ends; this provision, together with a slightly oblique position of the prongs, assures that rod-like material, which includes narrow cassettes containing a number of thin rods, carried by the prongs cannot slide off or roll from the prongs as the crane moves. In this manner, a relatively high speed of crane movement is possible; however, this speed is provided at the cost of the additional horizontal space required for the bosses or mandrels and the additional corridor width that then becomes necessary. Furthermore, at least rectangular material must be stored in the tiers of shelves with some distance from one piece to the next, so that there is a space between the rods of material for the bosses or mandrels to engage. Once again, this means additional space is required, or else stack shelves that are wider in the horizontal direction than is actually necessary must be provided, to hold a certain amount of material. As for the spacing between the rods of material in the tiers of shelves, there is also the danger that the rods may not be stored exactly parallel to one another, and so the spacing must then be increased still further to provide a margin of safety.